Hydraulic roll grinder



July 28,1953 B. A. wlLsoN 2,646,651

HYDRAULIC ROLL GRINDER Filed Feb. 15, 1949 4 sheets-sheet 1 @5NNWUANQHNII M a M. m SN@ @MENS m XS QQ Q m um@ @OS SQ RQ 3 Q July 28,1953 B. A. wlLsoN L 2,646,651

HYDRAULIC ROLL GRINDER Filed Feb. l5. 1949 4 Sheets-Sheet 2 I INVENTOR.@ma new., BY a a,

I July 28, 1953 B. A. wlLsoN HYDRAULIC ROLL GRINDER 4 Sheets-Sheet 3Filed Feb. 15, 1949 \INVENTOR.

1 /lun BY QM/@M July 28, 1953 B. A. WILSON HYDRAULIC ROLL GRINDER FiledFeb. l5, 1949 INVENTOR.

4 SheetsI-Sheet 4 Patented July 28, 1953 i 2,645,651 sri-c1?.

HYDRAULIC ROLL 'GRINDER Bert A. Wilson, Pittsburgh, Pa., assignor, bymesne assignments, to Blaw-Knox Company, Pittsburgh, Pa., acorporationof Delaware Application February 15, 1949, serial No.l 76,436 c1aims.(01.51-1om This invention relates to new and useful improvements incylindrical ro-ll grinding machines especially vadapted for use ingrinding large rolls for rolling mills.

It is among the objects of the invention to provide a roll grindingmachine which shall be hydraulically powered having a wide range ofspeed and operated by finger-tip control of a few control valves Withoutthe employment of gear Wheels.

It is a further object of the invention to provide an hydraulicallyoperated and controlled roll grinding machine having automatic controlmeans for grinding crowns or concavities on the roll surface.

Itis still a further object of the invention to provide hydraulicallyoperated roll grinding machines in which the several actuating parts'are separately powered by hydraulic pumps with relief valve controlsfor maintaining suitable fluid pressures and with means for bleeding offor venting any .air that may be pumped into the L system. s

Still another obj ect of the invention is the provision in an hydraulicroll grinding machine of an hydraulically actuated grinding Wheelcarriage or slide and control means for automatically actuating saidslide to grind a tapered or curved contour in response to axial movementof the roll table. f

These and other objects of the invention will become more apparent froma consideration of the accompanying drawings, constituting a parthereof, in which like reference characters designate like parts and inwhich Fig. 1 is va top plan view, partially cut away, of anhydraulically operated roll grindingmachine embodying the principles ofthis invention Fig. 2 a top plan View, partially in section,.of 'aportion of the machine bed and grinder wheel slide actuating bar;

Fig. 3 a vertical cross sectional view of a control valve for thegrinder slide;

Fig. 4 an end elevational View of the valve of Fig. 3;

Fig. 5 a side elevational view, partially'in section, oi' the valveshown in Figs. 3 and 4;

Fig. 6 a top plan View ci the roll grinder unit with a portion of thebed cutl away;

grinding machine unit;

Fig. 12 a cross sectional view of the table astuating lcylinder andplunger;

machine.

l2 Fig. 13 an end elevational view, partially in section, taken alongthe line I3-I3, Fig. 12; and Y Fig. 14 a diagrammatic view illustratingthe hydraulic actuating and control mechanism for the several operatingparts of the roll grinding With reference to Fig. 11 of the drawings,the reference numeral I generally designates the grinder bed having ways2 on which is mounted the grinder table 3 that carriesa head stock 4anda tail stock 5. Mounted on the bed I `and behind the table 2, asshown in Fig. 7, is a grinder base t on whichis supported acarriage 'I'for a grinding wheel 8 that is driven by a motor 9 through V-beltsmounted on pulleys Il) and II. The head stock 4 is driven by anhydraulic motor I2 by V-belt's mounted on pulleys I3 and I4, the latterdriving pulley I5 that drivesV the head spindle through pulley I6. Theheadstock and tail stock are provided `with centers Il and I8 on whichthe roll to be ground, such as the roll I9, Fig. 1, is mounted, the headstock carrying dogs 20 that interact with the spaces in the Wobbler'2Iof the roll I9.

The table 3, as shown in Fig. 7, is mounted for sliding movement in Ways22 and is actuated by an hydraulic cylinder 23, shown in detail in Fig.12 and in the diagrammatic view of Fig. 14. It is bolted to theunderside oi table 3 at drilled and tapped holes 24 and 25 in cylinderheads 26 and 2l, respectively, to be movable with the table. Thecylinder 23 may be stainless steel tubing of suitable dimension. Thevtwocylinder heads 29 andA 21 may be joined by bolts passing through drillholes 28 in the headsfrom head to'head. Gland'nuts 29 and 3U are screwedo-n heads 26 and 2l to secure the packing'glandsl and 32 and the pistonrod packing 33 and 34.

The piston head is made of four parts that consist of an internallythreaded sleeve 35 having leather` cups 36 and 3l on both sides thereof,which are held by heads 38 and V39 which are machined complementary tothe shape of the cups to hold them against the threaded sleeve 35 toconstitute a piston head. The heads 38 and 39 are counterbored Vandprovided with threads 40 and 4I. A plurality of seamless tube pistonrods 42 and 43 are threaded at their ends to interact With the threads40 and 4I. Drill holes 44 are provided in the piston heads 38 and 39 asshown. The other ends of rods 42 and43 are provided with threads 45 and46 to receive nuts 4l and 48. 'When assembled the rods extend throughbrackets 49 and 50 of the machine bedl. The end nuts 4l' and 48 of thepiston rods ride on roller supports 5I and52 and are adjustable relativeto the brackets 49 and 50 to provide an a-dinstable longitudinalmovement of the piston rod through the brackets. This movement occurs oneach reversal of the table 3, establishing a pause in its movement sothat when the table comes to the end of'the grinding cut or pass theroll or work being ground will make a revolution before the table startsback in reverse. Fig. 12 shows the end nuts in transition position whilethe rods 42, 43 are moving; it being understood that the table 3 is thenstationary in one extreme position. When one of the nuts 41, 48, abutsagainst a bracket 49 or 50 as the case may be, the rods and piston cometo and remain at rest and further ilow of oil into the cylinder 23causes the latter to move and propel the table 3 toward its other oropposite extreme position.

The end of travel of the table is also optionally controlled by anadjustable stop comprising an angle bracket or abutment 53 attached to aT-bar 54, Fig.V `l1, of the table and an angle bracket 55 attached tothe bed I. An adjusting screw 5E is provided to adjust the stop positionof the table at the end of its travel. This travel control means isutilized when grinding the journal necks 51 to bring the grinding wheelup against the shoulders 58 or the .shoulders 59 and B0, or whicheverportion of the roll is being ground. The table feed power vholds thetable against abutment 53 to provide chatterproof stop.

The hydraulic iluid for actuating the table is transmitted through theends of the piston rods 42 and 43 by conduits 6| and 82 which, as shownin Fig. 14 of the drawings, are connected to a four-way valve cylinder63 which is provided with a spool valve 64. Conduits 6| and 62 areconnected to ports 65 and 66 of valve housing 63 which is furtherprovided with a double port or gland 61 connected by a conduit 68 to asource of pressure fluid such as a pump E9 that is operated by a motor10, Fig. 14. Valve 63 is further connected bya conduit 1I to a valve 12that controls the rate of travel of the table. The fourway valve 63 isfurther connected by conduits 13 and 14 to a valve 15 for starting andstopping the table movement and a pilot valve 1E having iingers 11 inthe path of adjustable stops 18 and 19 is mounted on rod of carriageshown in Fig. 14, which reverses the movement of the table at the end ofthe table travel. A relief valve is disposed in the drain line 8| of thecontrol valve 15 leading to a sump 82 for the purpose of regulating thefluid pressure independently of the pressure of the fluid at its source,and for this purpose is provided with a valve adjustment 83.

To eliminate any air that may be pumped into the hydraulic operating andcontrol mechanisms, provision is made for the escape of air through aneedle valve 84 which is connected in the main pressure line 68 and isfurther connected by a transparent plastic tube 85 to the line 85leading from the feed valve 12 to the sump 82.

The grinding wheel head and its power mechanism is constructed asfollows. The slide 1 is mounted on four rollers 81, Fig. 7, and isfurther provided with side rollers 88, Fig. '1, to reduce friction, andis actuated in sliding movement by the piston rod |33 of an hydrauliccylinder 89 which is controlled selectively by manually controlledfour-way valve 9| that is actuated by a handle 92, or by automatic valve35 subsequently described and explained. The valve 9| is connected by apressure conduit 93 to a pump 94, Fig. 14, and is provided with a needlevalve 95 for bleeding out any air that may be pumped into line 93.

The grinder head in which the grinding wheel is journaled is shown indetail in Fig. 9 of the drawing. The grinding wheel 8 is rotated by aspindle 96 journaled at one end in ball bearings CII Sland at its otherend in a triple row staggered roller bearing 98. The inner race ofbearing 98 is seated on a conical or tapered portion of the spindle 96on which it is held by a sleeve |00 and a lock nut |0|. With thebearings 91 abutting the spindle shoulder |02 on one side and the ringnut I02a on the other, the spindle is locked against axial displacement.Bearings 91 maybe pressed off spindle 9B by a sleeve |03 against whichthe nut |0| acts when turned on the threaded portion |04 of the spindle.

The grinding wheel collet or mount is made of three parts, a hub |05 andwheel flanges |06 and |01 between which the abrasive wheel 8 is clampedby bolts |08. The end of spindle 96 is tapered as shown at |09, behindwhich the spindle is provided with -a square thread ||0 on which thewheel flange portion |01 is screwed. The wheel ange portion |01 is alsoprovided with countersunk cap bolts ||I, with which the hub |05 issecurely attached thereto.

The outer race I !2 of the triple staggered roller bearing 98 isinserted in sleeve H3 to which it is bolted. Sleeve I3 is 4held in wheelslide 1 by nut H4, and one end of the bearings 91 is held in place 'bynut H5. A second sleeve l I3 is held in slide 1 by nuts H1 and H8, inwhich is pressed the outer races of ball bearings 9,1, held by retainerIIB threaded into sleeve I6. The mounting of the abrasive wheel 8permits grinding closer, and the triple roller bearings 98 at thegrinding wheel end of the spindle, due to the out of line of ltherollers by staggering, gives a smoothness to the spindle and grindingwheel not attainable by ball bearings, and the cause of chattering orvibration on the work is eliminated. The spindle is driven by a pulleyor sheave wheel drive as previously described which is keyed on thetapered end of shaft 95 at Ila and the grinding wheel hub |05 is keyedon taper 'seat at the other end of shaft 96 at |0511.

The wheel slide 1 is provided with a screw feed H9 which is providedwith a bearing 20 at one end that is bolted to the machine bed I, and asecond bearing |2| that is also bolted to the machine bed Screw ||9 isprovided with square cut threads |22 that interact with the thread of ashoulder sleeve |23 having a key-way |24. An adjusting vscrew |25 keepsthe feed screw ||9 tight against ball thrust bearing |29. Screw I|9 isprovided with a gear wheel 21 that interacts with a pinion |28 rotatable'by a hand wheel |29 to afford micrometer adjustment of the screw H9.Sleeve |23 is a sliding nt in sleeve 30 held in bracket |3I. A key |32anchored in the bracket sleeve |30 prevents shoulder sleeve |23 fromturning when screw H9 is rotated 'to permit motion of the wheel slide 1towards the work by action of cylinder 39 as shown in Fig. l0. Theshoulder |32 is a stop for the wheel slide or rather the bracket I3|which is bolted to the wheel slide 1. This feed screw is not used toretract the grinding wheel, which is eiected simply by reversingcylinder 89 by operation of valve 9|.

The cylinder 89 for actuating the wheel slide hydraulically is bolted tothe bed I of the machine and its piston rod |33 is connected to bracket|3| by the screw |3311, Fig. l0, so, that when hydraulic pressure isapplied to cylinder $39 the pressure on the piston head |34 displacesbracket |31, carrying with it the wheel slide 1 to feed the grindingwheel 3 into the Work. The adjusting and actuating mechanism is securelyheld against any other displacement movement except that of eeding thewheel to the work.

against the shoulder or flange of .the-screw sleeve |23. lf the screwfeed ||9 is not adjustedand the wheel slide is reversed 'by the pressureinV cylinder 89 only, then upon the reversal of pressure which bringsslide |3| against the shoulder stop |23, the wheel is again in the samegrinding position that itrwas before reversal.

The grinder head slide 1 may also be automatically fed while the worktable is moving back and forth on the machine bed by means of an au'-tomatic valve, generally vdesignated by the ref-V erence character |35,shown in Figs. 2 to 5 inclusive. The automatic feed is used for grindingcrowns, concavities or tapered surfaces on the roll body and shoulders,for which purpose a bar |36, Fig. l, is employed. It is mounted bybracketsA |31 and |66' mounted on the table 3. The ends of the bar |36may be adjusted by micrometer screws |39 and |49,.and the center of thebar is pivotally mounted at |4| on a bracket. as shown, which is securedto the table 3. A contour bar |42, which normally is straight, ismounted on the 'bar |36. It is attached to the bar |36 by brackets |43and |44,.shown in detail toV the left at the rbottom of Fig.kl, and isprovided with an eccentric k|45 carried by a bracket |46 bolted to bar|36 as shown in the centerv at the bottom of Fig. l, the eccentric |45being adjustable to bow the bar |42 where it is desired to grind a crown|41 on the face o f the roll as shown in Fig. 1 in a manner to behereinafter explained. The automatic Valve |35 is controlled to feed thegrinder wheel slide 1 to form the crown on the roll by a follower |48which, as shown in Fig. 3, is mounted on a lever |49 pivoted at |50 tothe valve base. The follower 48 rides against the bar |42 as shown inFig. l. a slide bar that is connected to the slide 1 by a bracket |52asfshown in Fig. l, so that the Valve moves transversely ofthe table 3and synchronously with the grinder head -1 in response to actuation ofcylinder 89 which the valve controls. For the purpose of adjusting thegrinding wheel head to the work or tafble the bar |5| may be clamped tothe bed by yoke clamp |5|a as shown in Fig. 2. The bed 1 may then bemoved by sliding contact with bar |5| without disturbing valve |35.

One end of the bracket is connected to an arm |53, Fig. 5, of the valvebase |54. The base |54 is adjustable by a micrometer feed screw |55operated by hand wheel |56 to move the wheel slide in the direction ofthe roll to bring the wheel 8 in contact with the roll preliminary tothe automatic feeding as effected by the valve |35 in the followingmanner. 3, is biased by a spring |51 which is connected to a stud |58screwed into base |54 of the valve;the

' spring being absent in Fig. 5.

of the plunger |59. A special rubber packing cupv |64 is fastenedunderneath the plunger shoulder |63 by a screw |65. Av small reservoir|66 'is' pro- Y vided below the plunger which is lled with liquidVthrough the opening closed by a small screw |61.

f Cylinder |60 has an extended sleeve |68 in which The valve lever|49,Fig.`

The Valve is carried upon Aisjin'vsert'edV a piston rod |69, vapackingcup |18 being provided in the endof the extension sleeve v I68. A springcage |1| is screwed on theA piston rod |69, the cage being biased by acoil spring |12 that rests against a flange of the cageV and the otherend rests upon va spring seat |13. Ihe 'action of spring |12 is tomaintain pressure on the liquid in the reservoir |66. y

The piston rod |69 pushes against aspo'ol v alve |14 which is controlledby a spring |15 resting on body fiange |16. Spring |15 keeps pressure onthe spool valve |14 and on the'piston |69 and against the iiuidin thechamber |66, whereby pressure is maintained against plunger |59 andlever |49, but not enough to stretchor move spring |51.

The spool'yalve controls port holes ,|11and |18 which, as shown in Fig.14, are connected to the lower end of the wheel slide cylinder 89vandthe pressure side of pump 94 through conduits |19, a needle valve|88 being provided in the line and a relief Valve |8| having a drain |82to the sump l82. Port holes |83 and |84 are connected to the top andbottom of the cylinder 89 for the return flow of the fluid to thereservoir or sump through port holes |85 and |86. These connections areso made to expel any trapped air in the cylinder 89 when all port holesarecovered bythe spoolk valve |14,v and the fluid is not passing toeither end of the cylinder. The spool shape of the valve |14 provides apressure balance on all sides of the valve so that it is responsive onlytothe pressure vof the fluid acting through the respective ports of thevalve.V In other words, no power is lost or movement in thevalve'housing.

required in subjecting the spool valveto axial So long as the controlvalve is closed (i. e., follower |48 and lever |49 are not disturbed ormoved relative to the Valve body) the grinding wheelslideto which it isconnected by the slide bar |5| remains stationary or in a xed position,

and it will remain so as long as the contour bar |42 is parallel tothetable travel. i

When the bar |42 is set for tapering or crowning, roller |48 as itfollows the bar will displace lever,v |49 to presson plunger |59 whichin turn exerts pressure on the uid in reservoir 66, forcing the liquidto expand into the cylinder sleeve` brings the control valve back inbalance. The

shape of the contour bar will thus permit a small amount of pressurefluid to be fed to thecylinder ually controlled by pushing in or pullingout the slide |31.

When valve ,|14 is closed oil is trapped'in the cylinder 89 on bothsides of the fpiston,v and the grinder slide 1 is rigidly held againstdisplacevment in either direction. Movementof the lever |49 opens theports to both sides of the piston,one

to pressure and the other to the reservoir, to va degree proportionaltothe lever movement but `pair accuracy of control.

`rapidly as closed position is approached inhibits momentum elects anddelay in equalizing pressure on both sides of the piston which would im-Thus as shown in Fig. 14, the grinder Wheel slide 'l may behydraulically actuated either by the automatic control valve |35 or bylever 92 through valve 9| which is connected by conduits |88 and |89 tothe top and bottom of the cylinder 89, which for clarity is shown inFig. 14 of the drawings as connected both to the automatic control andmanual hydraulic controls.

The reservoir |66 functions as sensitizing means in the valve by whichsmall or iniinitesimal displacements of the plunger |59 (resulting fromcorresponding small displacements of lever |49 and roller |48) istranslated as large or substantial displacements of the valve operatingpiston |69. This result is due to the relative areas of the largeactuating plunger |59 and small actuated piston |59 'and the constantvolume of displacement transmitting oil reservoir |56. As an incrementof this oil is transferred from cylinder |69 to the small diameterextension |68 the lineal` displacements of the piston and plunger 4arenot only proportional to the magnitude of the increment of oiltransferred, but the valve motion is intensified in the ratio of areasof the moving parts and is therefore sensitive to minute and practicallyinnitesimal reactions between the roller |48 and contour bar |42.

With reference to Fig. 14 of the drawings, the head stock is driven byan hydraulic motorA |2 connected to a four-way valve cylinder |9| havinga spool valve |92 operated by a lever |93. The

valve |9| is connected by a conduit |94 to a pump |95 having a reliefvalve |96 to regulate the pressure of the fluid independently of thepressure at the pump.

Theways 22 of the bed on which table 3 slides are lubricated byproviding a reservoir |98 for oil in the bed of the machine as shown inFig. 2. This is covered by a pan |99 to keep Aout dust. The cover isprovided with a slot a little longer than the travel of the table 3 anda suction pipe 200 is attached to the table extending through the slotinto the reservoir |98. At the head stock end of the table is a smallmotor and pump 20|, the suction side of the pump being connected to thepipe 209 and the outlet side of the pump being connected to pipes 292and 2 03 which lead to the center of the table ways 22 to supplylubrication. This gives uniform pressure of lubrication throughout thetable travel and permits the oil to be returned through holes providedin the ways to the sump without further piping. The ways also arefurther provided with pockets 204 that are filled with Babbitt orplastic to catch any grit that may accumulate in the ways to prevent itfrom scratching the surface of the ways.

vtail stock center all as shown in Fig. 1, the work is set up forgrinding by the wheel 8.

The wheel slide 'l is initially moved adjacent the roll surface by thehand wheel |29 which moves the slide. The grinder wheel motor 9, Figs. 7and 11, is then energized to actuate the grinder wheel 9. The start andstop valve T5, Fig. 14, is then actuated to direct pressure fluid to thetable cylinder 23, Fig. 14. Stops 19 and '19 for valve 16 are then setto limit the length of travel of the table 3 to the distancecorrespending to the surface on the roll I9 to be ground. Valve 12 isthen adjusted to regulate the return of travel of the table back andforth and the wheel is then fed either by the hand wheel adjustment, asshown in Fig. l0, where the surface of the roll or shoulder is straight,or if crowned as shown in Fig. l of the drawing the automatic regulatorvalve |35 is brought into action by adjusting roller |48 to contact thesurface of the contour bar |42. If the bar |42 is bulged in the centerby an adjustment of the eccentric |45, Fig. 1, the travel of roller |48on the contour bar will result in a feeding of the wheel 8 through theslide 'I corresponding to the contour of the bar, resulting in a crownedsurface |41. If the contour bar |42 is merely thrown at an angle withoutbulging in the center, or tilted, so to speak, the resulting action ofthe roller |48 following the contour bar will produce a taper such asshown at 5T, Fig. l of the drawings, which is the journal neck of theroll.` The roll is actuated to rotate through the hydraulic motor |2 byoperating lever |93 that controls the valve |9|.

For speedy travel of the grinder wheel slide 'l to and away from thework, such as when the roll is removed and a new roll placed on thetable, the cylinder 89 is connected to the pressure fluid bymanipulating lever 92 which through valve 9| directs the iluid to movethe slide head either direction as desired.

The feed screw |9 for the grinding wheel slide with the sleeve and stopshoulder |23 acting to stop Ythe slide with the hydraulic cylinder 89pushing the Wheel slide against the stop, any movement except to feedthe wheel to the Work is eliminated. There is no back lash in the screwand nut and no wear. n 'Ihe lubrication of the table ways on the bed 1sanother desirable and important feature as it maintains equal pressureof the lubricant on all points of the table for the full length oftravel ofY the table. It eliminates piping, and supply of oil in unequalpressures resulting in a smoother gr1nding operation, and preventsscoring of the ways of the table and bed.

The staggered roller bearing 99 for the grinder head, as shown in Fig. 9of the drawings, produces a smoothness to the spindle operation notobtained by ball bearings or rollers that are in line instead 0fstaggered. It produces a smooth finish on the Work and permits deeperfeeding into the work, thereby reducingtime for the grinding operation.

Another important feature is the table operating cylinder with thecomposite piston head holding leather packing cups and the manner inwhich it operates to delay action to allow the work to make a revolutionbefore the table reverses. The adjustable stops on the bed permit ofgrinding against the shoulders and collars of the work and eliminate theneed for a rack on the table. The hydraulic actuators and controls allwithin the reach of the operator at the front of the table allow forspeedy adjustment and accurate control of the roll grinding operation.While the invention has been demonstrated as applicable to grinding ofrolling mill rolls, it isevident that it may be used for any kind ofgrinding operations and especially for large industrial parts.

Although one embodiment of the invention has been herein illustrated anddescribed, it will be evident to those skilled in the art that variousmodifications may be made in the details of construction withoutdeparting from the principles herein set forth.

I claim:

1. In a roll grinding machine, a bed having ways for receiving a table,a table mounted for sliding movement on said ways, an hydraulic cylindermounted on said table parallel to said ways, a floating piston in saidcylinder, hollow piston rods comprising iluid conduits extending throughboth ends of said cylinder connecting to said piston, fluid ports insaid piston communicating with the ends of said conduits respectively onopposite sides of said piston, guide means on said bed for said rodspermitting longitudinal movement of said rods therein, and stop means onsaid rods adapted to engage said guide means after limited displacementof said rod in both directions, and reversible valve means forselectively admitting iiuid to said cylinder under pressure through oneconduit and withdrawing fluid through said other conduit to cause saidtable to reciprocate along said ways, the said, limited displacement ofsaid rods and piston providing a predetermined interval upon reversal ofsaid valve during which the table remains stationary while the rods andpiston move to rest against said stop means.

2. In a roll grinding machine constructed according to claim 1, aheadstock and tail stock for receiving and turning work to be groundmounted on said table, means for driving said headstock continuously, agrinding wheel adjacent said table at a station iiXed longitudinally ofsaid ways, valve reversing fingers adjustably mounted on said table andadapted to engage and operate said reversible valve means when the tableis in extreme positions with the ends of the pass on the work at saidstation, and the said stop means. on said rods being mounted to provideone revolution at least of the continuously rotated work at said extremepositions while the table is stationary to complete grinding a fullcircumference at said extreme positions before reversal of said table.

3, In a roll grinding machine, a machine bed having ways for reaching atable, a table mounted for sliding movement on said ways, hydraulicactuating mechanism for operating said table comprising an hydrauliccylinder mounted on said table, a piston operative in said cylinder, asource of pressure iiuid for said cylinder and valve means for directingthe uid to opposite sides of said piston, said piston comprising aplurality of piston heads, a screw sleeve joining the ends of saidheads, hollow piston rods connected to said heads, said heads having uidchambers communicating with said piston rods and having iiow passagesfrom said chambers, cup leathers disposed between said heads forproviding fluid seals with the wall of the cylinder, and packing glandsbetween the cylinder heads and piston rods externally of the cylinder.

4. In a roll grinding machine, a machine bed, a table mounted forsliding movement on said bed, a slide for supporting a grinder wheelhead extending transversely of the path of movement of the table, agrinder head mounted on said slide carrying a grinding wheel, pressureiiuid means for moving said head to and away from said table, a valvefor controlling the application of pressure fluid for actuating saidgrinder wheel head, a templet mounted on the table, means for adjustingthe contact surface oi the ternpletl to the desired contour of the rollto be ground, means engaging said templet for operating said Valve inresponse to movement of said table, said valve comprising a valvehousing, a spool valve in said housing, ports controlled by said spoolvalve connected to a source of pressure iiuid and to a sump, springmeans normally biasing said spool valve to one position of its travel,fluid pressure means counteracting said spring means, and a lever forregulating the pressure on said iiuid pressure means, said lever beingbiased by a spring relative to its fulcrum point and a follower mountedon said lever for engaging the templet of the table to eiect movement ofthe spool Valve and for directing pressure iluid to and from theoperating cylinder oi the grinder wheel head in response to movement ofthe table.

5. In an hydraulic roll grinder including a work carrying tablereciprocable longitudinally and a grinder carriage movable transverselyof said table at a station therealong and a bed having longitudinal andtransverse ways for said table and carriage respectively, an hydrauliccylinder mounted in said bed connected to propel said carriage, atemplet adjustably mounted on said bed parallel to the path of saidcarriage, a control valve for said cylinder, mounting means supportingsaid valve adjacent said templet from said carriage, said means beingfrictionally held by said carriage, a clamp mounted on said bed adaptedto engage and hold said mounting means in xed relation to said templetand to permit said carriage to slide with respect to said mountingmeans, the valve and said mounting means being free to move incorrespondence with movement of said carriage when said clamp isreleased, whereby by operating said clamp the carriage may beindependently indexed to grind the work at a predetermined depth, andafter release of said clamp the contour and depth of grinding ascontrolled by interaction of said valve and templet.

BERT A. WILSON.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 957,978 Meyers I May 17, 1910 1,419,073 Norton June 6, 19221,633,557 Morgan June 21, 1927 1,953,029 Smith Mar. 27, 1934 2,079,720Shaw May 11, 1937 2,132,941 Flygare i Oct. 11, 1938 2,164,518 I-IartJuly 4, 1939 2,246,476 Wood et al. June 17, 1941 2,276,260 TurrettiniMar. 10, 1942 2,294,872 Wood Sept. 1, 1942 2,397,178 Wiken et al. 2 Mar.26, 1946 2,411,391 Robaczynski Nov. 19, 1946 2,436,373 Barnes Feb. 24,1948 2,475,791 Lesueur July 12, 1949 FOREIGN PATENTS Number Country Date209,696 Switzerland Apr. 30, 1940

